Advisers to Babcock International, which is trying to buy Peterhouse for £95m, are understood to have made submissions over Jackson's conduct.
The advisers are believed to have told the panel that it feared Jackson had contacted Peterhouse shareholders without independent consultants being present. Jackson denies the allegations.
Babcock is concerned that Jackson and fellow director Simon Foster could influence shareholders to vote against the deal. They have publicly recommended that shareholders do not accept the offer, arguing that it undervalued the group. The rest of the Peterhouse board is satisfied with the offer. Jackson and Foster made their own bid for the firm, but this collapsed in April.
I think Babcock is desperate. There is a lot of pressure on shareholders
David Jackson of Peterhouse
It is understood that a member of the Jackson–Foster faction was contacted by the panel over the accusation after the first complaint last week. A second complaint was made by Babcock's advisers early this week. Both were made by telephone.
Jackson said: "The only allegation that I have heard is that I have talked to shareholders. That is absolute nonsense."
Babcock and the takeover panel declined to comment.
Babcock has until Monday to obtain shareholder approval for the deal, otherwise it will be called off under takeover rules. At the start of this week, Babcock said it would go ahead with the takeover if it received more than 50% approval from shareholders. Before that it said it would complete the deal only if it received approval from 90%. Jackson claimed this indicated the strength of shareholder dissatisfaction with the offer. He added: "I think they are getting desperate. There has been a lot of pressure on shareholders but they won't vote for it because it is not a good deal."
A spokesperson for Babcock said: "It is not desperation. It is a sign that we want to achieve the acquisition."
It seems that Babcock will win over enough shareholders to go ahead with the purchase. At the time of going to press it had 47.2% approval. Schroder Investment Management has been increasing its stake in the past week. It is believed that Schroder backs the deal, so increasing its holding would push approval over 50%.